1. Field of the Invention
The present invention relates to an apparatus and method for automatically configuring virtual addresses for a duplicate address when the duplicate address is detected in a single subnet.
2. Description of the Related Art
Conventionally, when a new node enters a subnet, the new node sends a neighbor solicitation (NS) message to check whether there is a node having the same link local address as the new node in the subnet. If there is a node having the same link local address as the new node, the node informs the new node that there is a duplicate address by sending a neighbor advertisement (NA) message to the new node. If a duplicate address does not exist in the subnet, the new node sends a router solicitation (RS) message to a router and acquires prefix information of the subnet and router-related information through a router advertisement (RA) message. Through the above-described method, the address of the new node is automatically configured. When the new node generates a tentative address and transmits the tentative address by embedding it into an Internet Control Message Protocol (ICMP) field of the NS message, if the format of the tentative address is not an EUI-64 format, i.e., a standard for identifying a network interface address, but a format arbitrarily defined by a user, the likelihood of the occurrence of a duplicate address increases. Conventionally, duplicate address detection is first performed. If a duplicate address is detected, this fact is reported to a network manager, the network manger performs manual configuration, and a new node must wait until a new address is configured.
In addition, with an increase in the number of network terminals, the mobility of network terminals is enhanced, so the likelihood of duplication of interface identifications (IDs), i.e., the lower 64 bits of an Internet Protocol version 6 (IPv6) address, in the same subnet also increases. In other words, when media access control (MAC) addresses complying with various techniques use the network-layer IPv6 protocol, if an IPv6 address is duplicated, an address must be manually configured as described above. Consequently, address auto-configuration, which is a representative feature of the IPv6 address system, becomes useless.